At Foothills Park in Palo Alto, a mama deer and her family emerged from the woods and grazed in the meadow just beyond a crowded picnic area. They paid no mind to the dozens of onlookers.

In Marin County last weekend, on the slopes of Mount Burdell at Olompali State Park, many hikers had similar encounters. A multitude of deer, almost tame, were everywhere.

Yet on the western slopes of the high Sierra, you could go days and never see a deer.

In Yosemite Valley this summer, the combination of many bears scrounging for food and speeding cars on the park's roads resulted in 17 bears hit by cars. Last year, there were 19. Yet outside the park in wilderness on the Pacific Crest Trail, you could hike for weeks and never see a bear.

In the Sacramento National Wildlife Refuge, along the 6-mile driving tour this weekend, you might see 250,000 ducks and geese; last week, scientists counted more than 1.3 million ducks and nearly 400,000 geese on the refuge's six complexes. Yet a mile or two away in a hunter's duck blind, you could sit for hours and not see a single duck fly within a quarter mile.

Landmark changes in wildlife behavior in the past 25 years, caused by a variety of reasons, are transforming the scope of the outdoors in California.

These changes seem to reach everywhere and touch everything. In some cases, it's as if new strains of species are evolving:

The "suburban deer": A GPS collar tracking survey in the Bay Area and Sierra foothills found that most deer in California live their entire lives within a 5- or 6-mile radius. They are prolific at parks, golf courses and the yards of sprawling homes that adjoin open space areas. These deer are virtually domesticated and bear little resemblance to the mountain-bred mule deer of the northern part of the state that migrate according to weather and snow lines.

Sierra Nevada/Cascade deer: Gone are the great herds of wild deer that once migrated every fall from the high Sierra and Cascade ranges to their wintering grounds in the foothills. Best estimates say the number of deer in California has plummeted from 2 million in the 1960s to about 450,000 (of which most are "suburban deer"). Expanded highways and new subdivisions have blocked historic migration routes. Timber companies cut down forests and replanted them with conifers, which deer can't eat, so there's less food. Record-high populations of mountain lions eat a deer or two per week. Over 40 years, these factors created a synergism, and the big herds were devastated.

Mooching bears: Bears go to where there's easy food and away from where they might get shot. That's why there are so many bears in Yosemite Valley around the campgrounds - even when there are 15,000 people in a 2.5-square-mile area on a summer day - or along Highway 198 in Sequoia National Park. In wilderness, we used to see bears every trip. No more. In areas like the Golden Trout Wilderness, where people are few and those few use bear-proof canisters for food, the bears head elsewhere for easy pickings. You'll find the bears instead at drive-in campgrounds, summer cabins where people leave pet food, chicken feed or garbage outside, or cabins left vacant for extended periods.

Ducks: Back in the day, deep in a marsh in the Sacramento Valley, you could witness spectacular dawn fly-outs of waterfowl. The ducks would wake for the day and depart en masse from resting areas in the marsh to feed at nearby rice fields. No more. Ducks have become largely nocturnal in the Sacramento Valley. They feed at night and then pre-dawn, before shooting time, they return to the marsh to sleep or fraternize with other ducks in protected no-hunt zones. They have evolved to avoid hunters.

Striped bass: Forty-four years of pumping has turned the Sacramento-San Joaquin River Delta upside down. The pumps suck down 70,000 gallons of water per second and send it to points south, and with it go juvenile fish and eggs. Striped bass once spawned in great numbers, roughly 4.5 million adults, in the delta and associated waterways. They're all about gone. To survive, what's left of the striped bass population now spawns in the Sacramento River near Colusa, 125 miles north.

Elk: Just 30 years ago, elk were virtually nonexistent outside of Point Reyes National Seashore and Grizzly Island Wildlife Area near Suisun. Transplant programs and natural herd expansion have helped create 21 herds with about 3,800 animals. Unlike deer, elk can ward off predators such as mountain lions and coyotes and flourish in expanded range habitats not bound by roads or subdivisions. In the coming century, elk in the north part of the state will be the king of California big game.

Sierra bighorn: At one point, the population of Sierra bighorn sheep had dropped to about 100 animals, driven close to extinction by mountain lion kills and disease from domestic sheep. Selective lion control has been effective in protecting herds at Pine Creek (now about 115 animals) and Silver Canyon (about 40 animals) in the Eastern Sierra near Bishop. The state total is now about 400. One scientist from Yosemite told me that a new strain of Sierra bighorn has evolved that will not migrate below the snow line in the winter, as the species has done since the ice age, in order to avoid getting eaten by mountain lions.

Cal Hall of Fame

Nominations are open for the California Outdoors Hall of Fame. Candidates must fill two requirements: The nominees must have inspired thousands of Californians to take part in the great outdoors and/or conservation, and the nominees must have taken part in a paramount scope of adventure. Entries must include a 200-word biography. I am chairman of this year's event and will accept nominations at tstienstra@sfchronicle.com. The annual awards will be announced in January at the Sacramento International Sportsmen's Exposition, which sponsors the award. For more information: caloutdoorshalloffame.org.